This invention relates in general to coal processing devices and in particular to a new and useful discharge device for fluids containing heavy matter which includes a valve regulating discharge at separate flow levels in a flow stream through a vessel to a collecting bottom which includes means for sensing the level of the solids and for actuating the drain valves in the various levels accordingly.
The invention relates particularly to a discharge device for the discharge of heavy matter in settling machines for the processing of coal or other mineral raw materials by means of a bottom drain of variable opening cross section actuated by a device for sensing the heavy matter layer.
In settling machines for the processing of coal or other mineral raw materials, the heavy matter is often discharged by means of a bottom drain. The opening of the bottom drain is regulated in that the heavy matter bed is sensed by a float and a change in the height of the heavy matter bed brings about an adjustable change of the discharge opening.
To keep the volume of the heavy matter bed to be discharged constant, the drain must always draw off as much material as new heavy matter is supplied with the material being charged. For reasons of process engineering it is necessary that the geometry in the region of the drain be selected so that a reserve layer forms above the drain, having a layer thickness greater than in the forward region of the settling material support.
With the known discharge regulating systems it is indeed possible to act on the adjustment of the discharge as a function of the change in bed position and to make it relatively sensitive; but as the quantity of heavy matter to be discharged, increases the more difficult it becomes to discharge the heavy matter neatly.
Because of the large amount of waste to be discharged per unit time and because of the electrical and mechanical delay in the discharge control system, it may happen that not only heavy matter but also lighter matter is drawn into the drain. This is due to the fact that when larger amounts of heavy matter are being drawn off, a suction funnel, as it were, forms above the drain, since in the known drains the discharge occurs through a relatively narrow gap, i.e. practically in punctiform manner.